A coalition of largely liberal organizations has written a letter asking the Senate to extend the lame duck to allow as many of President Barack Obama's nominees to win confirmation before Republicans take control of the chamber.

The 33 signatories of the new letter include the American Federation of Labor and Congress of Industrial Organizations, the Communications Workers of America, the NAACP, the Natural Resources Defense Council and Public Citizen.

The letter, sent Monday to Majority Leader Harry Reid, D-Nev., and Minority Leader Mitch McConnell, R-Ky., calls for prolonging the second session of the 113th Congress to help clear the nomination decks, a move that would no doubt draw criticism from Republicans. The letter comes from the Fix the Senate Now coalition, a group that has advocated for a substantial overhaul of the Senate's rules.

"We urge you and your colleagues to fulfill the duties of the Senate, stay in session and vote on as many nominees as possible before the end of the 113th Congress. Longstanding vacancies in our government and courts will only make it more difficult to accomplish our goals and fulfill the needs of the American people," the letter said. "Thank you again for your leadership, and we look forward to continuing our work together in the future."